"The existence of distinct stem cell populations suggests that they give rise to different types of neurons, which explains the varied functions of the hippocampus," says Perry Bartlett. (Credit: Sarah Van Quickelberge/Flickr)

Researchers have identified two types of stem cells in the hippocampus, a region of the brain crucial for learning and memory.

Dhanisha Jhaveri, lead author of the new study, says the researchers have isolated pure populations of these cells for the first time.

The discovery may have implications for the treatment of learning- and mood-related disorders.

“The stem cells we have identified give rise to new neurons,” Jhaveri says. “The production of new neurons in the brain, a process that decreases as we age, is essential for learning and cognitive function.”

Professor Perry Bartlett, director of the Queensland Brain Institute, says the discovery solved a longstanding mystery about the birth of new neurons in the hippocampus.

“Previously, these neurons were all thought to be identical, so it wasn’t understood how the region is able to regulate behaviors as divergent as learning and mood,” he says.

“The existence of distinct stem cell populations suggests that they give rise to different types of neurons, which explains the varied functions of the hippocampus.”

“The two cell groups are located in different regions of the hippocampus, which suggests that distinct areas within the hippocampus control spatial learning versus mood,” says Jhaveri. “When we purified the cells we found that they are activated by different mechanisms, and generate new neurons that differ in their gene expression.”